VENOM PRODUCTION OF SPIDERS GENUS Loxosceles HEINECKEN & LOWE, 1839 (ARANEAE; SICARIIDAE): VARIATIONS RELATED TO THE SPECIES, SEX AND SEQUENTIAL EXTRACTIONS

MARQUES-DA-SILVA E.(1) & FISCHER M. L.(2)

(1) Seção de Animais Peçonhentos, Centro de Produção e Pesquisa de Imunobiológicos – SESA - Paraná; (2) Núcleo de Estudos do Comportamento Animal – CCBS – PUCPR.

Venomous spiders genus Loxosceles cause thousands of accidents all of the years in the Paraná state, Brazil. The high incidence of Loxoscelism in this state led to the production of loxoscelic antivenom by the Center of Production and Research of Imunobiologicals (CCPI). The Loxosceles spiders` venom was obtained by electric stimulation and crystallization by vacuum desiccation. Our objective was to analyze the variation in the productivity of the venom of females, males and juveniles (300 L. intermedia, 194 L. gaucho and 273 L. laeta) in successive extractions with a time interval of 20 days. Among the species more venom was extracted from L. laeta (0,075 mg/spider), followed by L. gaucho (0,066 mg/spider) and L. intermedia (0,058 mg/spider). For L. intermedia the female (0,09 mg/spider) produces 3 times more venom than males and juveniles; for L. gaucho the female (0,102 mg/spider) produce 2,3 times more venom than male and 5,6 times more than juveniles; for L. laeta the female (0,113mg/spider) produce 4 times more venom than males e 2,6 times than juveniles. The greater resistance to sequential extractions was shown by L. laeta being possible to extract up to 5 times (respectively 55%, 52%, 46% and 28% of survival rate). Individuals L. intermedia had their venom extracted up to 3 times (respectively 54% and 74% of survival rate); L. gaucho was extracted only 2 times (32% of survival rate). Any of the three species showed decrease in the average venom  production per spider in successive extractions. Venom production of the Loxosceles is related to the relative amount of males used, being related to the low amount of venom liberated by the male and with their low resistance to the electric stimulation.

KEY WORDS: spider, venom, L. gaucho, L. intermedia, L. laeta.

CORRESPONDENCE TO: EMANUEL MARQUES DA SILVA, Seção de Animais Peçonhentos, Centro de Produção e Pesquisa de Imunobiológicos (CPPI). R: Targino da Silva s/nº, Piraquara – Paraná – Brasil. CEP: 83302-160. Email: ems@pr.gov.br